Your Essential Guide to the Process of Injection Moulding

Injection moulding has produced a plethora of products and materials that we make use of every single day – from plastic packaging to automotive body parts, injection moulding has indeed contributed greatly to various industries and has shaped the perspective of modern living as we know it.

But if you are thinking of manufacturing a specific part, product, or component with the use of injection moulding, it always pays to know as much as you can about the entire process. This way, you will not be in the dark once the process begins and will be able to make better, more informed decisions for a precise and well-designed end product or part.

The characteristics of the injection moulding process: how it is done

The process of injection moulding makes use of a plunger shaped like a screw or a ram in order to force or pour a plastic material (which has been melted) into a specific mould. The plastic will then solidify into the precise contour and shape of the mould. Injection moulding is most often used for the production of different types of plastic parts or components, especially thermosetting and thermoplastic polymers. Thermoplastics, for one, are ideal for injection moulding, as they feature various characteristics that are suitable for the injection moulding process such as ease of recycling, an ability to become softer and flow smoothly once heated, and versatility, which allows them for use in many applications. Also, thermoplastics are more ideal for injection moulding than thermosetting polymers because they are safer to use – if a thermoset is not properly ejected in time from the barrel, then a chemical process can occur which can cause damage to the machinery used for injection moulding.


More on the injection moulding process: moulds

You already know that injection moulding is a process wherein a specific raw material (such as thermoplastic) is injected into a set mould, which then shapes the plastic or polymer into a specific shape. Obviously, moulds play a big role in the injection moulding process, as they dictate the end result of a part or product.

There are actually two types of moulds: those with only one cavity, and those with numerous cavities. For moulds with several cavities, one cavity can be made identical to another, or cavities can each have unique shapes which are different from each other. Moulds are most commonly comprised of steel, often tool steel, but also aluminium or stainless steel for specific applications. However, keep in mind that an aluminium mould is not often used for production of a high volume or for parts which have narrow dimensions. In addition, aluminium moulds are more likely to get damaged or be prone to deformation or wear and tear. However, for production of low-volume parts or components, aluminium moulds can suffice. Steel moulds, on the other hand, can have a longer lifespan and are actually designed to produce millions of parts or components. They can, however, be a lot more costly to produce and fabricate.

As you can see, the material of the mould chosen for the plastic injection moulding process is of great importance as well. It is therefore always best to work with a proven injection moulding specialist (such as so you can be sure that you are getting the quality and expertise you deserve.

Image attributed to Stuart Miles/

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